Clinical trials of IIb/IIIa receptor blockers in patients undergoing angioplasty.

Many major clinical trials have been published in the last decade involving a new class of antiplatelet agent-Glycoprotein IIb/IIIa receptor blockers. The largest experience to date with these has been in percutaneous coronary intervention. Seven trials involving three different agents (abciximab, tirofiban, eptifibatide) are discussed. Abciximab is the most widely studied agent and is the only drug licensed for use in this setting. All three agents reduce the incidence of clinically relevant ischaemic events (death, non-fatal myocardial infarction or urgent revascularization). The shorter acting, competitive inhibitors tend to be maximally beneficial during the time of infusion, whereas abciximab has been shown to be effective in the acute and long-term phases. The benefits of treatment are tempered by an increase in the bleeding complications. These can be minimized by changes in heparin dosing and careful management of vascular sheaths. The treatment benefit of abciximab is maintained in those patients with unstable angina, those undergoing atherectomy, vein graft angioplasty or bail out-stenting. Results from the Epistent trial, support the use of abciximab during elective stenting. Nevertheless, rapidly changing interventional techniques and the availability of other potent antiplatelet agents underscore the need for further evaluation of IIb/IIIa inhibition in coronary revascularisation.